Lubricating oil



Oct. 26, 1937. c. c. TowNE 2,097,245

LUBRIQATING OIL Filed March '7, 1934 h s, Zar/es Q'W//e INVENTOR ,5f/sATTORNEY Patented Oct. 26, 1937 2,097,245 vUUBRICATING OIL Charles C.Towne, Poughkeepsie, N. Y., assignor to The Texas Company, New York, N.Y., a corporation of Delaware Application March 7, 1934, Serial No.714,360

This invention relates to the manufacture of petroleum lubricating oils,and particularly oils of this character possessing a green uoresc'enceand other desirable properties.

One of the objects of this invention is to provide a petroleumlubricating oil possessing a green fluorescence froma. distillate oil,which is normally decient in that property, by utilization of cheap ornormally waste materials available at oil reiineries, such as iixedrefinery gases or oil gas from cracking stills.

depressant. i

Still another object of the invention is to provide. a method ofdewaxing a wax bearing oil by the employment of a wax crystal modifyingmaterial obtained from gaseous hydrocarbons of this character.

It is well known that certain distillate lubricating oils, which are ofexcellent quality as lubricants, are nevertheless deficient in theproperty of bloom. Certain Pennsylvania lubricating oils arereddish-brown by transmitted light and green by reflected light, therebypossessing what is termed a green bloomor fluorescence. In certaininstances, it has been considered desirable to impart tolubricating'oildistlllates which are deficient in this property ofbloom, a green iiuorescence similar to that which is characteristic ofPennsylvania base oils. It has heretofore been suggested that a greenbloom imparting material can be prepared fromthe residuum ofdistillation, either cracking or non-cracking, of a petroleum However,this has necessitated the employment, as starting materials, of mineraloils which could otherwise be used for the preparation of Furthermore,this has necessitated special distillation equipment and processing, inorder to produce a bloom impartoil.

more valuable products.

ing material of acceptable character.

14 Claims. (Cl. 196--10) propane, butane, etc., and mixtures thereof,may be employed for this purpose.

According to the present invention, the hydrocarbon gases are subjectedto high temperature pyrolysis in a cracking still. This may beaccomplished in connection with aplant for the manufacture of benzol andits homologues from hydrocarbon gases by pyrolysis thereof, inaccordance with my Patent No. 1,943,246 dated January 9, 1934, Hightemperature pyrolysis has the usual 10 significance of this term in theart,-namely, a pyrolysis in which the gases are passed through a heatingcoil or `zone at a temperature in excess of 1150 F., and generally attemperatures varying between 11502000 F. Known types of cat- 15 alystsmay be employed, either as porous catalysts within the heating tubes, oras materials constituting the heating tubes. The gases may be maintainedat substantially atmospheric pressure, or they may be passed through theheating 20 coil under superatmospheric pressures varying up to 500 lbs.per sq. in. or higher. The pyrolyzed gases are then passed to a coolingzone, such as awater cooled condenser, where the temperature iscontrolled to separate primarily high boiling 25 constituents, mainlyabove the boiling points of benzol and homologous hydrocarbons of thebenzene series. In this manner, there is condenseda liquid fractioncomprising a heavy black oil.; Depending upon the temperature ofcondensa-s@ tion, this material will usually comprise a small;A .Tfproportion of benzol and naphthalene in admix-l ture with a tarryresidue. The latter is found to be highly concentrated in green bloomimparting material. The condensate oil may be mixed directly with amineral lubricating oil to impart a green fluorescence thereto; or aconcentrated extract of bloom imparting material may be obtained fromthe condensate oil by suitable methods, such as distillation or solventextraction, and the concentrated extract then added to a minerallubricating oil.

Referring tothe drawing, in which the single figure is'a diagrammaticView of apparatus for carrying out the method of this invention, IIJindicates a cracking furnace containing a coil II through which thehydrocarbon gas is passed and heated to a high temperature such asordinarily used in gas pyrolysis operations. The products of pyrolysisare discharged into a water cooled condenser I2, to which cooling wateris supplied by line I3 and discharged by line I4.

- The products pass upwardly through tubes I5 of the condenser,uncondensed gases escaping by pipe I6 leading to a fractionating towerI1 where various lower boiling constituents, including benzol, may beseparated. 'I'he gas outlet temperature of the condenser I2 ispreferably controlled to about 400 F. or above, so that mainly highboiling constituents are condensed therein. These constituents form ablack oil which runs down the tubes i5, accumulating in the lowerportion of the condenser, and discharging by the line 20. Althoughnormally solid compounds are present in this oil, the liquidconstituents maintain them in solution, and clogging of the condenserdoes not occur.

This condensed oil may be added directly to a mineral lubricating oil toimpart a green bloom to the latter. Or, if desired, the condensed oilmay be treated or purified prior to use, such as by simple filtration,or by heating in contact with an adsorbent material followed byfiltration, or by acid treatment or other conventional treatmentsemployed in the refining of petroleum oils. This is indicatedin thedrawing, in which the pipe 20 discharges into a refining tank 2| towhich suitable chemical may be introduced by pipe 22. If desired, theoil may be treated to prepare a concentrate therefrom; as it is foundthat the bloom imparting materials in the oil consist mainly of highboiling constituents which remain in the tarry residue resulting fromreducing the oil by distillation, or are dissolved from the voil orresidue by solvent extraction. However, it is not necessary that any ofthese reiining or concentrating treatments be employed, as thecondensate recovered from condenser I2 may be satisfactorily marketed asa bloom imparting material. l

The condensate, whether treated or not in the refining tank 2l, ispassed by line 24 to either valve controlled'line 25 leading to receiver26, or valve controlled line 2`| leading to receiver 28. From thereceivers 26 and 28, the bloom oil or concentrate is passed by lines 29and 30 respectively to a blending tank 32, to which the lubricating oilto be treated is admitted by line 33. Only a small proportion of thebloom oil or concentrate need be added to a mineral lubricating oil toimpart a satisfactory green fluorescence thereto. Thus, less than 2% byweight of the condensate as obtained from condenser I2, or even asmaller proportionof extract. prepared therefrom, is ordinarily employedin blending with a distillate lubricating oil. The blended oil is thenpassed by line 36 to storage tank 36, from which it is withdrawn for useor further treatment by line 31.

As a specific example of the present invention,

an oil gas obtained from vapor phase cracking stills, is passed througha silica tube 20 mm. in diameter by 48 in. in length at the rate of 0.6cu. ft. per hour, the tube being maintained at a temperature of 14501500F. Issuing vapors are cooled in a water cooled condenser having a vaporoutlet temperature of approximately 450 F. A black condensate oil isthereby obtained in the amount of approximately 10 cc. per 4 to 5 cu.ft. of gas treated. 0.25 cc. of this oil dissolved in cc. of a paleMid-Continent distillate lubricating oil (Saybolt viscosity 300 at 100F.) so altered the appearance and bloom of the distillate oil that vitresembled a natural parailin base cylinder stock.

It has further been found that the shade of the bloom imparted to palelubricating oils by the product of this invention varies with thetemperature at which the latter is prepared. For example, where an oilgas from a vapor phase cracking still is pyrolyzed at a temperature ofapproximately 14501500 F., and a condensate oil recovered therefrom inthe manner described above, the green bloom imparted to a mineraldistillate oil is found to possess a slight bluish tinge. On the otherhand, where the same oil gas is passed through the same cracking stillat a temperature ofapproximately 16001700 F., the condensate oilrecovered therefrom, when added to the same pale lubricating oil,imparts a green bloom which has .a somewhat yellower tinge than that ofa usual Pennsylvania oil. By blending in suitable proportions theAcondensate oils prepared at different temperatures, and adding the blendto a distillate oil, a resulting bloom is obtained which approaches veryclosely the green bloom of a customary Pennsylvania oil, while at thesame time the reddish-brown color by transmitted light is substantiallythe same. 'I'he heat treatments at different temperatures may beaccomplished in separate cracking stills. Or, as shown, a singlecracking still may be employed; and a certain proportion of oil gaspassed through the furnace I0 at one temperature, the

condensate oil being collected in one of the receivers 26 or 28, andthen another portion of oil gas passed through the cracking furnace Ilat a different temperature, the condensate oil therefrom being collectedin the otherreceiver. The resulting bloom oils may then be blended inthe blending tank 32 by introduction in controlled proportions throughlines 29 and 30 from the rel.ceivers 26 and 28 respectively.

The products of the present invention as described above are also usefulas pour point depressants for lowering the pour point of a mineral oil.For example, the addition of a small proportion of a heavy condensationproduct recovered from the high temperature pyrolysis of a normallygaseous hydrocarbon of the character described above, to a partiallydewaxed lubricating oil derived from a paraffin base or a mixed basecrude, will materially lower the normal pour point of such lubricatingoil. It is recognised that the presence of a certain amount of wax in aparaffin base or mixed base lubricating oil may be beneficial from thestandpoint of providing a comparatively flat temperature-viscositycurve. However, the pour point of such a partially dewaxed lubricatingoil of this character is normally high, such as. around 25 F. or above.Consequently, it is of advantage to add to the oil a material which willhave the eect of reducing the pour test or cold test to the desiredextent without the necessity of entirely removing the remaining wax..The condensation product produced as outlined above may be addeddirectly to a lubricating stock; or an extract of the condensationproduct may be first prepared and this extract added to fthe lubricatingstock. Thus, a small proportion of the mineral oil to be treated, orother lubricating oil, may be used to form a concentrate of the activepour point depressant materials in the condensation product; and thisconcentrate can then be added in predetermined proportions to a largerbody of the oil to be treated. Again, different solvents may be employedto produce an extract of the condensation product. Suitable solventsinclude benzene,

' xylene, toluene and various aliphatic monohydric alcohols from methylto the amyl alcohols. The proportions in which the pour point depressantmaterial is added to the mineral lubricating oil can be Ivaried widely.However, it il usually desirable to add only that proportion tion withthe wax crystal modifying material and? which will lower the pour pointto the required low temperature. Generally, less than by weight of thepour point depressant material is used; and often as little as afraction of 1%, such as about 1/2 or less, is sufficient.

The products of the present invention are also useful in connection withthe removal of wax from a Wax bearing hydrocarbon oil. Thus, theaddition of a small proportion of the heavy condensate, or extractsthereof, recovered from the high temperature pyrolysis of a normallygaseous hydrocarbon of the character set out above, to a Wax bearingoil, is found to modify wax crystal formation upon chilling of the oil,to thereby facilitate separation of the wax from the oil by centrifugingor cold settling. It is also found that the addition of a wax crystalmodifying material of this character to a. wax bearing oil results insubstantially increasing filtering rates, where the wax is separatedfrom the chilled oil by filtration. The employment of products of thepresent invention along with a solvent in which both the solid andnormally liquid constituents are soluble at elevated temperatures of theorder of 100 F. or above, and in which the normally liquid constituentsare soluble but the normally solid constituents or waxes aresubstantially completely insoluble at lowered temperatures of the orderof 0 F. t0 -20 F., is found particularly beneficial. Various solvents ofthis character may be employed, such for example, as acetone, ethylenedichloride, methyl ethyl ketone, liquid sulphur dioxide, naphtha, propylalcohol and the like. Mixtures of such selective and non-selectivesolvent liquids are also satisfactory. For example, a very suitablesolvent mixture capable of serving as a dewaxing solvent consists ofacetone and benzol, for instance in the proportions of 35% acetone and65% benzol. Another very'suitable solvent mixture, particularly for thedewaxing of residual oils, consists of about 28-35% acetone, 47-5'7%benzol and 15-18% toluol. v

By way of example, a proportion of from l to by weight of the heavycondensation product obtained from the pyrolysis of oil gas, asdescribed above, may be added to a Wax bearing lubricating oil fraction,together with a solvent mixture of 35% acetone and 65% of benzol in theproportions of one part of oil to three parts of the acetone-benzolmixture. The oil is then chilled to a temperature of around 0 to 10 F.and subjected to settling at this temperature. The wax constituentssettle rapidly from the mixture, the supernatant liquid layer of oil andsolvent may be drawn off, and the solvent removed therefrom bydistillation. According to another method of operation, the chilledmixture may be subjected to centrifuging with satisfactory separation ofthe wax from the oil. In still another method of operation, the chilledmixture may be subjected to dewaxing by pressure filtra.- tion, and thefiltering rates be markedly increased over the rates obtained when thecondensation product of the present invention is not added. Where asolvent mixture of the charac- This is found beneficial when used inconjuncalso with the solvent or solventmixture.

Obviously many modifications and variations of the invention, ashereinbefore set forth, may' 1. A lubricating oil possessing a green11u0- rescence, comprising a mixture of a petroleum lubricating oil witha minor proportion of a heavy condensate recovered from the hightemperature pyrolysis of a normally gaseous hydrocarbon.

2. A lubricating oil possessing a green uorescence, comprising a mixtureof a petroleum lubricating oil with a minor proportion of a heavycondensate recovered from the high temperature pyrolysis of fixed gasesfrom a cracking still.

3. A lubricating oil possessing a green fluorescence, comprising amixture of a petroleum lubricating oil with a minor proportion 0f aheavy condensate recovered from the high temperature pyrolysis ofnatural gas.

4. A lubricating oil possessing a green liucrescence, comprising amixture of a petroleum lubricating oil with a minor proportion of aheavy condensate recovered from the high temperature pyrolysis of oilrefinery waste gases.

5.v A lubricating oil possessing a. green uorescence, comprising amixture of a petroleum lubricating oil normally deficient in bloom, withan'amount up to 2% byv weight of a heavy condensate formed by pyrolysisat temperatures in excess of 1150 F. of a normally gaseous hydrocarbonsuiiicientvto impart the said green fluorescence to the lubricating oil.

6. A lubricating oil possessing a green fluorescence, comprising amixture of a petroleum lubricating oil with a minor proportion of ablend of heavy condensates formed by high temperature pyrolysis of anormally gaseous hydrocarbon, one condensate of the blend being formedby pyrolysis at a diiierent temperature from that of another condensateto thereby give a resultingy blend of a controlled color and bloom.

7. A lubricating oil possessing a green fluoresence, comprising amixture of a petroleum distillate lubricating oil which is normallydeficient in bloom, with an amount up to 2% by weight of a heavycondensate oil recovered from the pyrolysis of oil gas at temperaturesof l4501700 F., sufdcient to impart the said green fluorescence to thelubricating oil.

8. A lubricating oil possessing a green fluorescence, comprising amixture of petroleum distillate lubricating oil, with an amount up to 2%by weight of a blend of heavy condensate oils formed by high temperaturepyrolysis of oil gas sufficient to impart the said green fluorescence tothe lubricating oil, one condensate oil resulting from pyrolysis at atemperature of 1450"- 1500 F., and another condensate oil resulting frompyrolysis at a temperature of 16001700 F.

9. The method of producing a green bloom lubricating oil, whichcomprises passing a normally gaseous hydrocarbon through a heating zonemaintained at a temperature in excess of 1150 F. to pyrolyze the gas,cooling the pyrolyzed gas to recover therefrom a heavy condensate whichis concentrated in green bloom imparting material, and adding aproportion of the heavy condensate to a petroleum lubricating oil.

10. 'I'he method of producing a green bloom lubricating oil, whichcomprises passing one por- 76 tion of a normally gaseous hydrocarbonthrough a heating zone maintained at a temperature in excess of 1150 F.to pyrolyze the gas, passing another portion of a normally gaseoushydrocarbon through a heating zone maintained at a diilerent,

temperature but also in excess of 1150 F.'to pyrolvze the gas, coolingthe pyrolyzed gases to recover therefrom heavy condensates which areconcentrated in green bloom imparting materials, and adding thecondensates in controlled proportions to a petroleum lubricating oil toimportions of each of the heavy condensates with a petroleum distillatelubricating oil which ls normally deficient in the property o! bloom tolmpart to the latter a green bloom of controlled shade.

12. A lubricating oil having a low pour point, comprising a mixture of apartially dewaxed lubricating oil normally having a higher pour pointwith a small proportion of a heavy condensate recovered from the hightemperature pyrolysis of a normally gaseous hydrocarbon.

13. A lubricating oil of improved character comprising a mixture of apetroleum lubricating oil with a minor proportion of a heavy condensateboiling essentially above 400 F. recovered from the high temperaturepyrolysis of a normally gaseous hydrocarbon.

14. A lubricating oil possessing a green fluorescence, comprising amixture of a petroleum lubricating oil with a minor proportion o! aheavy condensate recovered from the high temperature pyrolysis of anormally gaseous unsaturated hydrocarbon.

' CHARLES C. TOWNE.

